Head-up display

ABSTRACT

A head-up display includes an image generation unit emitting light for generating a predetermined image and a mirror reflecting the light so that a transmission member is irradiated with the light emitted by the image generation unit. The image generation unit includes a light source, an optical member transmitting light from the light source, and a liquid crystal portion in which an original image for forming the predetermined image is generated by the light emitted from the optical member. The original image is formed in a shape corresponding to distortion of the predetermined image. The optical member is formed in a shape matching the shape of the original image.

TECHNICAL FIELD

The present disclosure relates to a head-up display.

BACKGROUND ART

In the future, it is expected that there will be a mixture of thevehicles traveling in an automatic operating mode and the vehiclestraveling in a manual operating mode on public roads.

Visual communication between vehicles and humans is expected to becomeincreasingly important in the future automatic operating society. Forexample, visual communication between the vehicle and an occupant isexpected to become increasingly important. With respect to this point,the visual communication between the vehicle and the occupant can berealized by using the head-up display (HUD). The head-up display canallow the occupant. to be visually recognized or can realize so-calledAR (augmented reality) by projecting an image or a video onto thewindshield or the combiner and superimposing the image on an actualspace through the windshield or the combiner.

As an example of the head-up display, Patent Literature 1 discloses adisplay device including an optical system for displaying athree-dimensional virtual image by using a transparent display medium.The display device projects light into a field of view of a driver onthe windshield or the combiner. A portion of the projected light istransmitted through the windshield or the combiner, but another portionis reflected by the windshield or the combiner. This reflected lightfaces the eyes of the driver. The driver perceives the reflected lightthat enters the eyes of the driver as the background of the actualobject seen through the windshield or the combiner and the virtual imageseen like an image of an object on the opposite side (outside of thecar) with of the windshield or the combiner interposed.

CITATION LIST Patent Literature

-   Patent Literature 1: JP2018-45103A

SUMMARY OF INVENTION Technical Problem

By the way, existing head-up displays have room for improvement of thevisibility of virtual images (images).

Therefore, an object of the present disclosure is to provide a head-updisplay capable of improving visibility of a virtual image.

Solution to Problem

According to an aspect of the present disclosure, there is provided ahead-up display configured to display a predetermined image, the head-updisplay including:

-   -   an image generation unit emitting light for generating the        predetermined image; and    -   a mirror reflecting the light so that a transmission member is        irradiated with the light emitted by the image generation unit,    -   in which the image generation unit includes:    -   a light source;    -   an optical member transmitting light from the light source; and    -   a liquid crystal unit in which an original image for forming the        predetermined image is generated by the light emitted from the        optical member,    -   in which the original image is formed in a shape corresponding        to distortion of the predetermined image, and    -   in which the optical member is formed in a shape matching the        shape of the original image.

In addition, according to another aspect of the present disclosure,there is provided a head-up display configured to display apredetermined image, the head-up display including:

-   -   an image generation unit emitting light for generating the        predetermined image; and    -   a mirror reflecting the light so that a transmission member is        irradiated with the light emitted by the image generation unit,    -   in which the image generation unit includes at least:    -   a plurality of light sources; and    -   a single optical member transmitting light from each of the        plurality of light sources and emitting the light, and    -   in which the plurality of light sources are disposed at of the        mirror so that light emitted from the single optical member is        diffused and is incident on the mirror.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide a head-updisplay capable of improving visibility of a virtual image.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a vehicle system provided with a head-updisplay (HUD) according to an embodiment.

FIG. 2 is a schematic diagram illustrating a configuration of the HUD ofFIG. 1 .

FIG. 3A is a diagram illustrating an example of a light emission surfaceimage generated by an image generation unit of an HUD according toComparative Example.

FIG. 3B is a diagram when the light emission surface image illustratedin FIG. 3A is displayed as a virtual image.

FIG. 4 is a diagram illustrating an example of a light emission surfaceimage generated by an image generation unit of the HUD according to thepresent embodiment.

FIG. 5 is a diagram illustrating a virtual image object recognized whenthe light emission surface image illustrated in FIG. 4 is reflected by aconcave mirror.

FIG. 6 is a horizontal cross-sectional view of the image generation unitprovided in the HUD of the first embodiment.

FIG. 7 is a schematic view of the image generation unit of FIG. 6 asviewed from the front side.

FIG. 8 is a schematic view of an image generation unit provided in anHUD of a second embodiment as viewed from the above.

FIG. 9 is a partially enlarged view illustrating a shape of a lensprovided in the image generation unit of FIG. 8 .

FIG. 10 is a schematic top view of an image generation unit provided inan HUD of the related art.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention (hereinafter referredto as the present embodiment) will be described with reference to thedrawings. The dimensions of each member illustrated in this drawing maydiffer from the actual dimensions of each member for convenience ofexplanation.

In addition, in the description of the present embodiment, forconvenience of the description, the terms of “leftward-rightwarddirection”, “upward-downward direction”, and “front-back direction” maybe referred to as appropriate. These directions are relative directionsset for an HUD (head-up display) 20 illustrated in FIG. 2 . Herein, the“leftward-rightward direction” is a direction including the “leftwarddirection” and the “rightward direction”. The “upward-downwarddirection” is a direction that includes the “upward direction” and the“downward direction”. The “forward-backward direction” is a directionthat includes the “forward direction” and the “backward direction.”Although not illustrated in FIG. 2 , the leftward-rightward direction isa direction perpendicular to the upward-downward direction and theforward-backward direction.

A vehicle system 2 including the HUD 20 according to the presentembodiment will be described below with reference to FIG. 1 . FIG. 1 isa block diagram of the vehicle system 2. The vehicle 1 provided with thevehicle system 2 is a vehicle (automobile) capable of traveling in anautomatic operating mode.

As illustrated in FIG. 1 , the vehicle system 2 includes a vehiclecontrol unit 3, a sensor 5, a camera 6, a radar 7, an HMI (human machineinterface) 8, a GPS (global positioning system) 9, a wirelesscommunication unit 10, and a storage device 11. In addition, the vehiclesystem 2 also includes a steering actuator 12, a steering device 13, abrake actuator 14, a brake device 15, an accelerator actuator 16, and anaccelerator device 17. Furthermore, the vehicle system 2 has the HUD 20.

The vehicle control unit 3 is configured to control traveling of thevehicle 1. The vehicle control unit 3 is configured with, for example,at least one electronic control unit (ECU). The electronic control unitincludes a computer system (for example, SoC (System on a Chip), or thelike) including one or more processors and memory, and an electroniccircuit configured with active elements such as transistors and passiveelements such as resistors. The processor includes, for example, atleast one of a CPU (central processing unit), an MPU (micro processingunit), a GPU (graphics processing unit), and a TPU (tensor processingunit). The CPU may be configured with a plurality of CPU cores. The GPUmay be configured with a plurality of GPU cores. The memory includes ROM(read only memory) and RAM (random access memory). A vehicle controlprogram may be stored in the ROM. For example, the vehicle controlprogram may include an artificial intelligence (AI) program forautomatic operating. The AI program is a program (a learned model)constructed by supervised or unsupervised machine learning (especiallydeep learning) using multilayer neural networks. The RAM may temporarilystore the vehicle control program, vehicle control data and/orsurrounding environment information indicating surrounding environmentof the vehicle 1. The processor may be configured to load the programdesignated from various vehicle control programs stored in the ROM ontothe RAM and execute various processes in cooperation with the RAM. Inaddition, the computer system may also be configured with a non-vonNeumann computer such as ASIC (application specific integrated circuit)or FPGA (field-programmable gate array). Furthermore, the computersystem may be configured with a combination of a von Neumann computerand a non-von Neumann computer.

The sensor 5 includes at least one of an acceleration sensor, a velocitysensor, and a gyro sensor. The sensor 5 is configured to detect thetraveling state of the vehicle 1 and output traveling state informationto the vehicle control unit 3. The sensors 5 may be further providedwith a seating sensor that detects whether the driver is sitting in thedriver seat, a face direction sensor that detects the direction of thedriver face, an external weather sensor that detects external weatherconditions, a human sensor that detects whether or not there is a personin the vehicle, and the like.

The camera 6 is, for example, a camera including an imaging device suchas a CCD (charge-coupled device) or a CMOS (complementary MOS). Thecamera 6 includes an external camera 6A and an internal camera 6B.

The external camera 6A is configured to acquire image data representingthe surrounding environment of the vehicle 1 and then transmit the imagedata to the vehicle control unit 3. The vehicle control unit 3 acquiresthe surrounding environment information based on the transmitted imagedata. Herein, the surrounding environment information may includeinformation on objects (pedestrians, other vehicles, marker lights, andthe like) existing outside the vehicle 1. For example, the surroundingenvironment information may include information on the attributes ofobjects existing outside the vehicle 1 and information on the distancesand positions of the objects relative to the vehicle 1. The externalcamera 6A may be configured as a monocular camera, or may be configuredas a stereo camera.

The internal camera 6B is disposed in the vehicle 1 and is configured toacquire image data representing an occupant. The internal camera 6Bfunctions, for example, as an eye tracking camera that tracks theviewpoint E of the occupant (described later with reference to FIG. 2 ).The internal camera 6B is provided, for example, in the vicinity of aroom mirror or in an instrument panel.

The radar 7 includes at least one of a millimeter wave radar, amicrowave radar, and a laser radar (for example, a LiDAR unit). Forexample, the LiDAR unit is configured to detect the surroundingenvironment of the vehicle 1. In particular, the LiDAR unit isconfigured to acquire three-dimensional mapping data (point cloud data)representing the surrounding environment of the vehicle 1 and thentransmit the three-dimensional mapping data to the vehicle control unit3. The vehicle control unit 3 specifies the surrounding environmentinformation based on the transmitted three-dimensional mapping data. TheHMI 8 is configured with an input unit that receives an input operationfrom the driver and an output unit that outputs traveling informationand the like to the driver. The input unit includes a steering wheel, anaccelerator pedal, a brake pedal, an operating mode switch for switchingthe operating mode of the vehicle 1, and the like. The output unit is adisplay (excluding HUD) that displays various traveling information.

The GPS 9 is configured to acquire current location information of thevehicle 1 and output the acquired current location information to thevehicle control unit 3.

The wireless communication unit 10 is configured to receive informationon other vehicles around the vehicle 1 (for example, travelinginformation and the like) from other vehicles and transmit informationon the vehicle 1 (for example, traveling information and the like) tothe other vehicles configured (vehicle-to-vehicle communication). Inaddition, the wireless communication unit 10 is configured to receiveinfrastructure information from infrastructure equipment such as trafficlights and marker lights and to transmit the traveling information ofthe vehicle 1 to the infrastructure equipment (road-to-vehiclecommunication). In addition, the wireless communication unit 10 isconfigured to receive information on the pedestrian from a portableelectronic device (a smartphone, a tablet, a wearable device, or thelike) carried by the pedestrian and transmit the own vehicle travelinginformation of the vehicle 1 to the portable electronic device(pedestrian-to-vehicle communication). The vehicle 1 may directlycommunicate with the other vehicles, the infrastructure equipment, orthe portable electronic devices in an ad-hoc mode or may communicate viaan access point. Furthermore, the vehicle 1 may communicate with theother vehicles, the infrastructure equipment, or the portable electronicdevices via a communication network (not illustrated). The communicationnetwork includes at least one of the Internet, a LAN (local areanetwork), a WAN (wide area network), and a RAN (radio access network).Wireless communication standards are, for example, Wi-Fi (registeredtrade mark), Bluetooth (registered trade mark), ZigBee (registered trademark), LPWA, DSRC (registered trade mark), or Li-Fi. In addition, thevehicle 1 may communicate with the other vehicles, the infrastructureequipment, or the portable electronic devices using the fifth generationmobile communication system (5G).

The storage device 11 is an external storage device such as an HDD (harddisk drive) or an SSD (solid state drive). The storage device 11 maystore two-dimensional map information or three-dimensional mapinformation and/or vehicle control programs. For example, thethree-dimensional map information may be configured withthree-dimensional mapping data (point cloud data). The storage device 11is configured to output the map information and the vehicle controlprogram to the vehicle control unit 3 in response to the request fromthe vehicle control unit 3. The map information and the vehicle controlprogram may be updated via the wireless communication unit 10 and thecommunication network.

When the vehicle 1 travels in the automatic operating mode, the vehiclecontrol unit 3 automatically generates at least one of a steeringcontrol signal, an accelerator control signal, and a brake controlsignal based on the traveling state information, the surroundingenvironment information, the current location information, the mapinformation, and the like. The steering actuator 12 is configured toreceive the steering control signal from the vehicle control unit 3 andcontrol the steering device 13 based on the received steering controlsignal. The brake actuator 14 is configured to receive the brake controlsignal from the vehicle control unit 3 and control the brake device 15based on the received brake control signal. The accelerator actuator 16is configured to receive the accelerator control signal from the vehiclecontrol unit 3 and control the accelerator device 17 based on thereceived accelerator control signal. Thus, the vehicle control unit 3automatically controls the traveling of the vehicle 1 based on thetraveling state information, the surrounding environment information,the current location information, the map information, and the like.That is, in the automatic operating mode, the traveling of the vehicle 1is automatically controlled by the vehicle system 2.

On the other hand, when the vehicle 1 travels in the manual operatingmode, the vehicle control unit 3 generates the steering control signal,the accelerator control signal, and the brake control signal inaccordance with manual operations of the driver on the acceleratorpedal, the brake pedal, and the steering wheel. Thus, in the manualoperating mode, since the steering control signal, the acceleratorcontrol signal, and the brake control signal are generated by the manualoperations of the driver, at the traveling of the vehicle 1 iscontrolled by the driver.

As described above, the operating mode includes the automatic operatingmode and the manual operating mode. The automatic operating modeincludes, for example, the fully automatic operating mode, the advancedoperating support mode, and the operating support mode. In the fullyautomatic operating mode, the vehicle system 2 automatically performsall traveling control including steering control, brake control andaccelerator control, and the driver is not in the state where thevehicle 1 can be operated. In the advanced operating support mode, thevehicle system 2 automatically performs all traveling control includingthe steering control, the brake control, and the accelerator control,and the driver does not operate the vehicle 1 although the vehicle 1 isready to be operated. In the operating support mode, the vehicle system2 automatically performs a portion of traveling control out of thesteering control, the brake control, and the accelerator control, andthe driver operates the vehicle 1 under the operating support of thevehicle system 2. On the other hand, in the manual operating mode, thevehicle system 2 does not automatically perform traveling control, andthe driver operates the vehicle 1 without the operating support of thevehicle system 2.

The HUD 20 is configured to display the HUD information as the imagefacing the occupant of the vehicle 1 so that predetermined information(hereinafter referred to as HUD information) is superimposed on theactual space (in particular, the surrounding environment in front of thevehicle 1) outside the vehicle 1. The HUD information displayed by theHUD includes, for example, the vehicle traveling information related tothe traveling of the vehicle 1 and/or the surrounding environmentinformation related to the surrounding environment of the vehicle 1 (inparticular, information related to the object existing the outside ofthe vehicle 1), or the like. The HUD 20 is an AR display that functionsas a visual interface between the vehicle 1 and occupants.

The HUD 20 includes an image generation unit 24 and a control unit 25.

The image generation unit (PGU: picture generation unit) 24 isconfigured to emit light for generating a predetermined image to bedisplayed to the occupant of the vehicle 1. The image generation unit 24can emit light for generating a changing image that changes according toa situation of the vehicle 1, for example.

The control unit 25 controls operations of each unit of the HUD 20. Thecontrol unit 25 is connected to the vehicle control unit 3 and controlsthe operations of each unit of the HUD 20 such as the image generationunit 24 based on the vehicle traveling information, the surroundingenvironment information, and the like transmitted from the vehiclecontrol unit 3. The control unit 25 is provided with the processor suchas the CPU and the memory, and the processor executes the computerprogram read from the memory to control the operations of the imagegeneration unit 24 and the like. In this embodiment, the vehicle controlunit 3 and the control unit 25 are provided as separate components, butthe vehicle control unit 3 and the control unit 25 may be configuredintegrally. For example, the vehicle control unit 3 and the control unit25 may be configured with a single electronic control unit.

FIG. 2 is a schematic diagram of the HUD 20 viewed from the side of thevehicle 1. At least a portion of the HUD 20 is located in the vehicle 1.Specifically, the HUD 20 is provided at a predetermined location in thevehicle 1. For example, the HUD 20 may be located in a dashboard of thevehicle 1.

As illustrated in FIG. 2 , the HUD 20 has an HUD body unit 21. The HUDbody unit 21 has a body housing 22 and a light emission window 23. Thelight emission window 23 is configured with a transparent platetransmitting visible light. The HUD body unit 21 includes an imagegeneration unit 24, a control unit 25, and a concave mirror 26 (anexample of the mirror) in the body housing 22.

The image generation unit 24 is provided in the body housing 22 so as toface the front of the HUD 20. The image generation unit 24 has a lightemission surface 110 (an example of the liquid crystal unit) emittinglight for generating an image toward the outside. The light emissionsurface 110 is provided with a predetermined light emission region 110Aemitting light for generating the predetermined image to be displayed tothe occupant of the vehicle 1. The predetermined light emission region110A will be described later with reference to FIG. 4 .

The concave mirror 26 is disposed on an optical path of the lightemitted from the image generation unit 24. The concave mirror 26 isconfigured to reflect the light emitted from the image generation unit24 toward a windshield 18 (for example, the front window of the vehicle1). The concave mirror 26 has a reflection surface curved in a concaveshape to form the predetermined image and reflects the image of thelight emitted from the image generation unit 24 and formed into an imageat predetermined magnification. The concave mirror 26 may have, forexample, a drive mechanism 27 and may be configured to change theposition and orientation of the concave mirror 26 based on the controlsignal transmitted from the control unit 25.

The control unit 25 generates the control signal for controlling theoperations of the image generation unit 24 based on the vehicletraveling information, the surrounding environment information, and thelike transmitted from the vehicle control unit 3 and transmits thegenerated control signal to the image generation unit 24. In addition,the control unit 25 may generate the control signal for changing theposition and orientation of the concave mirror 26 and transmit thegenerated control signal to the drive mechanism 27.

The light emitted from the light emission surface 110 of the imagegeneration unit 24 is reflected by the concave mirror 26 and emittedfrom the light emission window 23 of the HUD body unit 21. Thewindshield 18 which is the transmission member is irradiated with thelight emitted from the light emission window 23 of the HUD body unit 21.A portion of the light with which the windshield 18 is irradiated fromthe light emission window 23 is projected into the viewpoint E of theoccupant. As a result, the occupant recognizes the light emitted fromthe HUD body unit 21 as the virtual image (predetermined image) formedat the predetermined distance in front of the windshield 18. As a resultof the image displayed by the HUD 20 being superimposed on the actualspace in front of the vehicle 1 through the windshield 18 in this way,the occupant can visually recognize a virtual image object I formed bythe predetermined image to remain on the road outside the vehicle.

Herein, the viewpoint E of the occupant may be either the viewpoint ofthe left eye or the viewpoint of the right eye of the occupant.Alternatively, the viewpoint E may be defined as the midpoint of a linesegment connecting the viewpoint of the left eye and the viewpoint ofthe right eye. The position of the viewpoint E of the occupant isspecified based on, for example, the image data acquired by the internalcamera 6B. The position of the viewpoint E of the occupant may beupdated at a predetermined period or may be determined only once whenthe vehicle 1 is started.

When forming a two-dimensional image (planar image) as the virtual imageobject I, the predetermined image is projected so as to be the virtualimage at the single distance determined freely. When forming athree-dimensional image (stereoscopic image) as the virtual image objectI, the plurality of predetermined images that are the same as ordifferent from each other are projected so as to be virtual images atdifferent distances. In addition, the distance of the virtual imageobject I (the distance from the viewpoint E of the occupant to thevirtual image) can be appropriately adjusted by adjusting the distancefrom the image generation unit 24 to the viewpoint E of the occupant(for example, by adjusting the distance between the image generationunit 24 and the concave mirror 26).

Incidentally, since the light emitted from the light emission surface110 of the image generation unit 24 is reflected by the concave mirror26, the distortion occurs in the virtual image object I recognized bythe occupant as the predetermined image due to the reflection by theconcave mirror 26. Therefore, it is desirable, for example, to correctthe distortion of the virtual image object I that occurs in order toallow the occupant to accurately recognize the information of thevirtual image object I.

Next, distortion occurring in the virtual image object and processingfor correcting the distortion (correction by warping of the image) willbe described with reference to FIGS. 3A, 3B, 4, and 5 .

FIG. 3A is a diagram illustrating an example of, as the image generatedby the light emitted from the image generation unit of the HUD accordingto Comparative Example, the image on the light emission surface 310 ofthe image generation unit, that is, an image (hereinafter referred to alight emission surface image) 312 generated by the light before beingreflected by the concave mirror. In addition, FIG. 3B is a diagramillustrating a virtual image object X recognized by the occupant as thepredetermined image after the light emission surface image 312illustrated in FIG. 3A is reflected by the concave mirror. It is notedthat information indicating a traveling speed (50 km/h) of the ownvehicle is displayed in the images illustrated in FIGS. 3A and 3B.

As illustrated in FIG. 3A, when the light emission surface image 312 onthe light emission surface 310 of the image generation unit according toComparative Example is a normal image, for example, an image on which apredetermined correction process with respect to the distortion causedby being reflected by the concave mirror is not performed, the virtualimage object X generated by the light reflected by the concave mirror isvisually recognized as an image having a distorted shape, as illustratedin FIG. 3B. In the case of Comparative Example, the virtual image objectX is visually recognized as the curved image in which the upper side iselongated and the lower side is contracted.

On the other hand, in the image generation unit 24 of the HUD 20according to the present embodiment, in order to correct the distortionof the image caused by being reflected by the concave mirror 26, aninverse correction process (also called correction process by warping)is performed on the light emission surface image in advance) isperformed.

FIG. 4 is a diagram illustrating an example of a light emission surfaceimage 112 generated by the light emitted from the image generation unit24 of the HUD 20. FIG. 5 is a diagram illustrating the virtual imageobject I recognized by the occupant as the predetermined image after thelight emission surface image 112 illustrated in FIG. 4 is reflected bythe concave mirror 26.

As illustrated in FIG. 4 , the light emission surface 110 of the imagegeneration unit 24 is formed in a rectangular shape and is provided withthe predetermined light emission region 110A for emitting light forgenerating the predetermined image. The light emission surface image 112is generated in the predetermined light emission region 110A by thelight emitted from the predetermined light emission region 110A. In thelight emission surface image 112 of this example, similarly toComparative Example illustrated in FIGS. 3A and 3B, a speed image isdisplayed to notify that a current traveling speed is 50 km/h,

The predetermined light emission region 110A of the rectangular lightemission surface 110 is formed, for example, as an annular fan-shapedlight emission region. The annular fan-shaped predetermined lightemission region 110A is a light emission region forming a rectangulardisplay range 114 in which the virtual image object I illustrated inFIG. 5 is displayed. The predetermined light emission region 110A isformed, for example, so as to occupy a region in which the annular fanshape is maximized on the light emission surface 110 in order to formthe large display range 114.

In the examples illustrated in FIGS. 4 and 5 , a correction process bywarping is performed on the light emission surface image 112 of thepredetermined light emission region 110A. In order to correct thedistortion caused by the reflection from the concave mirror 26, thelight emission surface image 112 of the predetermined light emissionregion 110A is corrected in advance by extending the upper side of theimage by the amount distorted by the reflection of the concave mirror 26and is corrected by shrinking the lower side of the image.

As can be seen from the virtual image object X in FIG. 3B, for example,a degree of distortion generated in the virtual image object I based onthe reflection by the concave mirror 26 decreases as it approaches thecentral region of the virtual image object I and increases as the endregion is away from the central region. For this reason, the correctionamount by warping performed on the light emission surface image 112,which is the original image of the virtual image object I, differsdepending on the position of the light emission surface image 112corresponding to the magnitude of the degree of distortion according tothe portion of the virtual image object I. For example, the correctionamount of the light emission surface image in the region correspondingto the center of the virtual image object I is relatively small, and thecorrection amount of the light emission surface image in the regioncorresponding to the end away from the center of the virtual imageobject I is relatively large.

As described above, the light emission surface image 112, which is theoriginal image for forming the predetermined image, is formed in a shapeon which an inverse correction process is performed so as to bedistorted in the opposite direction in advance by the amount distorteddue to the reflection by the concave mirror 26. For this reason, asillustrated in FIG. 5 , when the light that generates the light emissionsurface image 112 is reflected by the concave mirror 26, ahorizontally-long rectangular virtual image object I without distortionis visually recognized.

First Embodiment

Next, an HUD 20A according to a first embodiment will be described withreference to FIGS. 6 and 7 .

FIG. 6 is a horizontal cross-sectional view of an image generation unit24A provided in the HUD 20A. FIG. 7 is a schematic diagram of the imagegeneration unit 24A viewed from the front side (light emission surface110 side).

As illustrated in FIG. 6 , the image generation unit 24A includes alight source board 120 on which a plurality of light sources 121 (inthis example, seven light sources including a first light source 121A toa seventh light source 121G) are mounted, a lens 130 (an example of anoptical member) disposed at the front side of the light source 121, anda light emission surface 110 disposed on the front side of the lens 130.The image generation unit 24A further includes a lens holder 140disposed on the front side of the light source board 120, a heat sink150 disposed on the back side of the light source board 120, and a PGUhousing 160.

The light source 121 (first light source 121A to the seventh lightsource 121G) is, for example, a laser light source or an LED lightsource. The laser light source is, for example, an RGB laser lightsource configured to emit red laser light, green light laser light, andblue laser light, respectively. The first light source 121A to theseventh light source 121G are disposed on the light source board 120 tobe away a certain distance in the leftward-rightward direction. Thelight source board 120 is, for example, a printed circuit board made ofan insulator in which electrical circuit wiring is printed on a surfaceor inside of the board.

The lens 130 has an incident surface 132 on which light from the lightsource 121 is incident and a light emission surface 133 from which theincident light is emitted. The lens 130 is, for example, an asphericalconvex lens in which both the incident surface 132 and the lightemission surface 133 have convex surface shapes. The lens 130 isconfigured to transmit or reflect the light emitted from light source121 to emit the light toward the light emission surface 110. A prism, adiffusion plate, a magnifying glass, and the like may be appropriatelyadded to the lens 130 functioning as an optical member.

The lens 130 is configured by disposing the seven aspherical convexlenses corresponding to the first light source 121A to the seventh lightsource 121G in parallel in the leftward-rightward direction. Portions ofadjacent aspherical convex lenses of the lens 130 are combined inparallel. The lens 130 has a first region 131A transmitting the firstlight emitted from the first light source 121A, a second region 131Btransmitting the second light emitted from the second light source 121B,a third region 131C transmitting the third light emitted from the thirdlight source 121C, a fourth region 131D transmitting the fourth lightemitted from the fourth light source 121D, a fifth region 131Etransmitting the fifth light emitted from the fifth light source 121E, asixth region 131F transmitting the sixth light emitted from the sixthlight source 121F, and a seventh region 131G transmitting the seventhlight emitted from the seventh light source 121G. An incident surface132A of the first region 131A, an incident surface 132B of the secondregion 131B, an incident surface 132C of the third region 131C, anincident surface 132D of the fourth region 131D, an incident surface132E of the fifth region 131E, an incident surface 132E of the sixthregion 131F. and an incident surface 132G of the seventh region 131G areincident surfaces convex backward. A light emission surface 133A of thefirst region 131A, a light emission surface 133B of the second region131B, a light emission surface 133C of the third region 131C, a lightemission surface 133D of the fourth region 131D, a light emissionsurface 133E of the fifth region 131E, a light emission surface 133E ofthe sixth region 131F, and a light emission surface 133G of the seventhregion 131G are light emission surfaces convex forward. The lens 130 isattached to the lens holder 140 so that the centers of the lightemission surfaces of the first light source 121A to the seventh lightsource 121G are the respective focal positions.

The light emission surface 110 is a liquid crystal display, a DMD(digital mirror device), or the like. The light emission surface 110forms light for generating an image with the light of the light source121 passing through the lens 130. The light emission surface 110 isattached to a front surface portion of the PGU housing 160 with thelight emission surface facing the front of the image generation unit24A. The drawing method of the image generation unit 24A may be a rasterscan method, a DLP method, or an LCOS method. When the DLP method or theLCOS method is adopted, the light source 121 of the image generationunit 24A may be an LED light source. It is noted that, when the liquidcrystal display method is adopted, the light source 121 of the imagegeneration unit 24A may be a white LED light source.

The lens holder 140 holds the lens 130 in the PGU housing 160 so thatthe light emitted from the light source 121 is correctly incident on theincident surface 132 of the lens 130.

The heat sink 150 is made of aluminum, copper, or the like, which hashigh thermal conductivity. The heat sink 150 is provided so as to be incontact with the back surface of the light source board 120 in order toradiate heat generated from the light source board 120.

The lights emitted from the first light source 121A to the seventh lightsource 121G are incident on the incident surfaces 132A to 132G of thelens 130, respectively. Since the shape of the lens 130 is a shape inwhich the seven aspherical convex lenses are combined in parallel asdescribed above, most of the light emitted from the first light source121A is incident on the first region 131A of the lens 130 to be lightparallel to an optical axis 125A as illustrated for example in a firstoptical path 122A and is emitted from the first region 131A to beincident on the light emission surface 110. Although illustration isomitted, similarly, most of the lights emitted from the second lightsource 121B to the seventh light source 121G are incident on the secondregion 131B to the seventh region 131G, respectively, to be lightsparallel to respective axes of the second light source 121B to theseventh light source 121G and are incident on the light emission surface110.

As illustrated in FIG. 7 , the lens 130 is formed by stacking sevenaspherical convex lenses disposed in parallel in the leftward-rightwarddirection corresponding to the light sources in the plurality of stagesin the upward-downward direction. The lens 130 of this example is formedby staking the first region 131A to the seventh region 131G (an exampleof the convex surface portion) disposed in parallel in theleftward-rightward direction corresponding to the first light source121A to the seventh light source 121G and the eighth region H to thefourteenth region 131N (an example of the convex surface portion)disposed in parallel in the leftward-rightward direction correspondingto the eighth light source 121H to the fourteenth light source 121N intwo stages in the upward-downward direction. It is to be noted that eachlight source 121 indicated by a broken line is disposed behind the lens130.

The annular fan-shaped predetermined light emission region 110A isformed on the light emission surface 110, and thus, the light emissionsurface image (50 km/h) 112, which is an original image of thepredetermined image forming the virtual image object I, is generated inthe predetermined light emission region 110A. Then, the correctionprocess by warping is performed on the light emission surface image 112.

The lens 130, in which the first region 131A to the seventh region 131Gand the eighth region 131H to the fourteenth region 131N are stacked intwo stages in the upward-downward direction, is formed to have a shapematching the shape of the light emission surface image 112 on which thecorrection process by warping is performed. Specifically, the lens 130is formed in a curved-line shape matching the shape of the lightemission surface image 112 on which the corrected by warping isperformed. The first region 131A to the seventh region 131G of the lens130 are disposed so that a virtual lines connecting the respectivecenters of the light emission surface 133A to the light emission surface133G are curved line as viewed from the front. Similarly, the eighthregion 131H to the fourteenth region 131N of the lens 130 are disposedso that the virtual lines connecting the respective centers of the lightemission surface 133H to the light emission surface 133N are curvedlines as viewed from the front.

In addition, in the first light source 121A to the seventh light source121G corresponding to the first region 131A to the seventh region 131Gare disposed so that the virtual lines connecting these light sourcesare curved lines to match of the shape of the light emission surfaceimage 112 corrected by warping. Similarly, the eighth light source 121Hto the fourteenth light source 121N corresponding to the eighth region131H to the fourteenth region 131N are also disposed so that the virtuallines connecting these light sources are curved lines.

Among the first region 131A to the seventh region 131G in the lens 130,the fourth region 131D which is disposed in the central portion is alens emitting light for forming the central region of the light emissionsurface image 112. In addition, among the first region 131A to theseventh region 131G, the first region 131A and the seventh region 131Gwhich are disposed at the ends away from the central portion are lensesemitting for forming the end regions of the light emission surface image112. Similarly, among the eighth region 131H to the fourteenth region131N in the lens 130, the eleventh region 131K which is disposed in thecentral portion is a lens emitting light for forming the central regionof the light emission surface image 112. In addition, among the eighthregion 131H to the fourteenth region 131N, the eighth region 131H andthe fourteenth region 131N which are disposed at the end portions awayfrom the central portion are lenses emitting light for forming the endregions of the light emission surface image 112.

As described above, the degree of distortion occurring in the virtualimage object I based on the reflection by the concave mirror 26decreases as the virtual image object I approaches the central region,and the degree of distortion increases as the end region is away fromthe central region. For this reason, the correction amount by warpingperformed on the light emission surface image 112, which is the originalimage of the virtual image object I, becomes small in the regioncorresponding to the center of the virtual image object I in the lightemission surface image 112 and becomes large in the region correspondingto the end away from the center of the virtual image object I in thelight emission surface image 112.

It is preferable that the first region 131A to the fourteenth region131N of the lens 130 are formed so that there is a difference betweenthe region emitting the light for forming the central region of thelight emission surface image 112 and the region emitting the light forforming the surrounding region of the light emission surface image 112.For example, the first region 131A to the fourteenth region 131N may beconfigured so that there is a difference in curvature of the lightemission surfaces 133A to 133N according to the degree of distortiongenerated in each region (each of the central region, the end region,and the intermediate region) of the virtual image object I based on thereflection by the concave mirror 26.

As described above, the HUD 20A according to the first embodimentincludes the image generation unit 24A emitting light for generating thepredetermined image and the concave mirror 26 for reflecting the lightemitted by the image generation unit 24A, with which the windshield 18is irradiated. The image generation unit 24A includes the light source121, the lens 130 transmitting the light from the light source 121, andthe light emission surface 110A of the light emission surface 110 onwhich the original image for forming the predetermined image isgenerated by the light emitted from the lens 130. The original image isformed in a shape corresponding to the distortion of the predeterminedimage, and the lens 130 is formed in a shape matching the shape of theoriginal image. Specifically, the light emission surface image 112,which is the original image, is formed in advance in a shape so ascorrect the distortion of the predetermined image caused by thereflection of the light emission surface image 112 by the concave mirror26. The lens 130 is formed in a shape matching the shape of the lightemission surface image 112 as viewed from the light emission surface 110side. In addition, in order to correct the distortion of the imagecaused by the reflection by the concave mirror 26 of the light emissionsurface image 112 (original image) displayed in the predetermined lightemission region 110A of the light emission surface 110, an inversecorrection process (correction process by warping) is performed inadvance on the light emission surface image 112 to be displayed on lightemission region 110A. According to the configuration of the HUD 20,since the shape of the lens 130 (the first region 131A to the seventhregion 131G and the eighth region 131H to the fourteenth region 131N) isformed matching the shape of the light emission surface image 112, autilization efficiency of the light emitted from the light source withrespect to the predetermined light emission region 110A in which thelight emission surface image 112 corrected by warping is displayed canbe improved. As a result, the visibility of the virtual image object Ican be improved.

In addition, according to the HUD 20A, the shape of the lens 130 is acurved-line shape. When the rectangular virtual image object I isdesired to be displayed toward the occupant, it is preferable that thelight emission surface image 112 (original image) is formed in acurved-line shape in consideration of the correction process by warping.The utilization efficiency of the light emitted from the lens 130 towardthe predetermined light emission region 110A of the light emissionsurface 110 by forming the lens 130 in the curved-line shape matchingthe curved-line shape of the light emission surface image 112 can beeasily improved.

In addition, according to the HUD 20A, the light source 121 includes thefirst light source 121A to the fourteenth light source 121N, and thelens 130 includes the first region 131A to the fourteenth region 131N,which are the plurality of convex surface portions transmitting thelight from the first light source 121A to the fourteenth light source121N, respectively. The first light source 121A to the seventh lightsource 121G and the eighth light source 121H to the fourteenth lightsource 121N are disposed on a curved line as viewed from the lightemission surface 110 side, and the first region 131A to the seventhregion 131G and the eighth region 131H to the fourteenth region 131N aredisposed on a curved line as viewed from the light emission surface 110side. According to this configuration, since the plurality of lightsources and the plurality of convex surface portions are used, theutilization efficiency of the light emitted to the predetermined lightemission region 110A of the light emission surface 110 can be improvedeven when, for example, a large-sized virtual image object I isdisplayed.

In addition, according to the HUD 20A, the predetermined image (virtualimage object I) is formed in a horizontally-long rectangular shape, anda degree of distortion of end regions of the predetermined image islarger than a degree of distortion of a central region of thepredetermined image. Then, according to a difference between the degreeof distortion of the central region and the degree of distortion of theend regions, there is a difference in shape between the convex surfaceportion disposed corresponding to the central region and the convexsurface portion disposed corresponding to the end regions among thefirst region 131A to the fourteenth region 131N, which are the pluralityof convex surface portions. The end regions of the virtual image objectI are more likely to be distorted due to reflection by the concavemirror 26 than the central region. Therefore, by allowing the shape ofthe convex surface portion (for example, the fourth region 131D and theeleventh region 131K) disposed on the central side and the shape of theconvex surface portion (for example, the first region 131A, the seventhregion 131G, the eighth region 131H, and the fourteenth region 131N)disposed on the end sides to be different from each other, the imagedistortion can be appropriately corrected.

Second Embodiment

An HUD 20B according to a second embodiment will be described withreference to FIGS. 8 and 9 .

FIG. 8 is a schematic diagram of an image generation unit 24B providedin the HUD as viewed from the above. As illustrated in FIG. 8 ,similarly to the image generation unit 24A of the first embodiment, evenin the case of the image generation unit 24B, a plurality of lightsources and lenses configured to correspond to these light sources areprovided. In the example illustrated in FIG. 8 , five light sources of afirst light source 221A to a fifth light source 221E are provided. Thefirst light source 221A to the fifth light source 221E are disposed inparallel in the leftward-rightward direction. The lens 230 is a singlelens obtained by disposing five aspherical convex lenses correspondingto the first light source 221A to the fifth light source 221E inparallel in the leftward-rightward direction and combining portions ofthe adjacent aspherical convex lenses in parallel.

The lens 230 has a first region 231A transmitting a first light emittedfrom the first light source 221A, a second region 231B transmitting asecond light emitted from a second light source 221B, a third region231C transmitting a third light emitted from a third light source 221C,a fourth region 231D transmitting a fourth light emitted from a fourthlight source 221D, and a fifth region 231E transmitting a fifth lightemitted from a fifth light source 221E. An incident surface 232A of thefirst region 231A, an incident surface 232B of the second region 231B,an incident surface 232C of the third region 231C, an incident surface232D of the fourth region 231D, and an incident surface 232E of thefifth region 231E are incident surfaces that are convex backward. Alight emission surface 233A of the first region 231A, a light emissionsurface 233B of the second region 231B, a light emission surface 233C ofthe third region 231C, a light emission surface 233D of the fourthregion 231D, and a light emission surface 233E of the fifth region 231Eare light emission surfaces that are convex forward.

It is to be noted that the members having the same reference numerals asthose of the image generation unit 24A of the first embodiment have thesame functions, and the description thereof will be omitted asappropriate.

The first light source 221A to the fifth light source 221E are disposedat a pitch matching the shape of the concave mirror 26 so that the lightbeing irradiated from the first light source 221A to the fifth lightsource 221E, passing through the lens 230, and being emitted from thelight emission surface 233 of the lens 230 is diffused toward theconcave mirror 26 to move forward. The light sources are disposed sothat pitches P1 to P4 of the first light source 221A to the fifth lightsource 221E are shorter than pitches P5 to P8 of the vertices of thelight emission surfaces 233A to 233E of the lens 230.

For example, the pitch P1 between the first light source 221A and thesecond light source 221B is shorter than the pitch P5 between the vertexof the light emission surface 233A of the first region 231A and thevertex of the light emission surface 233B of the second region 231B inthe lens 230. Similarly, the pitch P2 between the second light source221B and the third light source 221C is shorter than the pitch P6between the vertex of the light emission surface 233B of the secondregion 231B and the vertex of the light emission surface 233C of thethird region 231C of the lens 230. The pitch P3 between the third lightsource 221C and the fourth light source 221D is shorter than the pitchP7 between the vertex of the light emission surface 233C of the thirdregion 231C and the vertex of the light emission surface 233D of thefourth region 231D. of the lens 230. The pitch P4 between the fourthlight source 221D and the fifth light source 221E is shorter than thepitch P8 between the vertex of the light emission surface 233D of thefourth region 231D and the vertex of the light emission surface 233E ofthe fifth region 231E of the lens 230.

The first light source 221A to the fifth light source 221E are disposedso that the light emitted from the light emission surface 233 of thelens 230, with which the concave mirror 26 is irradiated from the firstlight source 221A to the fifth light source 221E and passes through thelens 230 is substantially perpendicular incident on the concave mirror26. For example, the first light source 221A to the fifth light source221E are disposed so that the light passing through the optical axis ofthe lens 230 or the light passing through a path close to the path ofthe light passing through the optical axis is substantiallyperpendicularly incident on the concave mirror 26.

For example, the first light source 221A is disposed so that a light L1passing through the optical axis in the first region 231A or a pathclose to the path of the light passing through the optical axis amongthe light being irradiated from the first light source 221A, passingthrough the first region 231A of the lens 230, and being emitted fromthe light emission surface 233A is substantially perpendicularlyincident on the concave mirror 26. Similarly, the second light source221B is disposed so that a light L2 passing through the optical axis inthe second region 231B or a path close to the path of the light passingthrough the optical axis among the light being irradiated from thesecond light source 221B, passing through the second region 231B of thelens 230, and being emitted from the light emission surface 233B issubstantially perpendicularly incident on the concave mirror 26. Thethird light source 221C is disposed so that a light L3 passing throughthe optical axis in the third region 231C or a path close to the path ofthe light passing through the optical axis among the light beingirradiated from the third light source 221C, passing through the thirdregion 231C of the lens 230, and being emitted from the light emissionsurface 233C is substantially perpendicularly incident on the concavemirror 26. The fourth light source 221D is disposed so that a light L4passing through the optical axis in the fourth region 231D or a pathclose to the path of the light passing through the optical axis amongthe light being irradiated from the fourth light source 221D, passingthrough the fourth region 231D of the lens 230, and being emitted fromthe light emission surface 233D is substantially perpendicularlyincident on the concave mirror 26. The fifth light source 221E isdisposed so that a light L5 passing through the optical axis in thefifth region 231E or a path close to the path of the light passingthrough the optical axis is substantially perpendicularly incident onthe concave mirror 26 among the light which the light emission surface233E is irradiated with from the fifth light source 221E, passes throughthe fifth region 231E of the lens 230, and is emitted from the lightemission surface 233E.

Furthermore, the first region 231A to the fifth region 231E (examples ofthe convex surface portions) of the lens 230 are formed so that there isa difference in shape between the region emitting the light for formingthe central region of the light emission surface image and the regionemitting the light for forming the surrounding region of the lightemission surface image. For example, the shape of the third region 231Cwhich emits light for forming the central region of the light emissionsurface image, is formed so as is symmetrical in the leftward-rightwarddirection among the first region 231A to the fifth region 231E. On theother hand, the shapes of the first region 231A, the second region 231B,the fourth region 231D, and the fifth region 231E that emit light forforming the surrounding region of the light emission surface image areformed so as to be asymmetrical in the leftward-rightward direction. Thedegree of the asymmetry is larger in the regions that emit the light forforming ends of the light emission surface image. In the first region231A, the second region 231B, the fourth region 231D, and the fifthregion 231E, the degree of the asymmetry of the first region 231A andthe fifth region 231E is larger than the degree of the asymmetry of thesecond region 231B and the fourth region 231D.

FIG. 9 is a diagram illustrating the asymmetry of the shape of the firstregion 231A in the lens 230. As illustrated in FIG. 9 , the first region231A is disposed so that the inclination (degree of curvature) of acurved surface 233A1 on the left side (the side farther from the secondregion 231B) in the light emission surface 233A is gentler than theinclination (degree of curvature) of a curved surface 233A2 on the rightside (the side closer to the second region 231B) in the light emissionsurface 233A. That is, the light emission surface 233A is formed so thatthe curvature of the curved surface 233A1 on the left side is smallerthan the curvature of the curved surface 233A2 on the right side.Although not illustrated, similarly, the second region 231B is formed sothat the curvature of the light emission surface 233B on the side closerto the first region 231A is smaller than the curvature of the lightemission surface 233B on the side closer to the third region 231C. Adifference in curvature between the left side and the right side of thelight emission surface is formed so that the curvature of the lightemission surface 233A of the first region 231A is larger than thecurvature of the light emission surface 233B of the second region 231B.

On the other hand, although illustration is omitted, the fifth region231E is formed so that the curvature of the light emission surface 233Eon the right side (the side farther from the fourth region 231D) issmaller than the curvature of the light emission surface 233E. on theleft side (the side closer to the fourth region 231D). In addition, thefourth region 231D is formed so that the curvature of the light emissionsurface 233D closer to the fifth region 231E is smaller than thecurvature of the light emission surface 233D closer to the third region231C. A difference in curvature between the left side and the right sideof the light emission surface is formed so that the curvature of thelight emission surface 233E of the fifth region 231E is larger than thecurvature of the light emission surface 233D of the fourth region 231D.

Although FIG. 8 illustrates the image generation unit 24B viewed fromthe above, similarly, the shape of the lens may be changed for eachregion even when the image generation unit 24B is, for example, viewedfrom the left side or the right side)/For example, when the lens has theplurality of convex surface portions stacked in the upward-downwarddirection, the shape of the convex surface portion for emitting lightfor forming the central region of the light emission surface image andthe shape of the convex surface portion for emitting light for formingthe upper and lower end regions of the light emission surface image maybe allowed to be different from each other.

By the way, in an image generation unit mounted on the HUD, of therelated art, for example, as illustrated in FIG. 10 , a pitch Py betweenthe vertices of the (convex surface portion) was the same pitch. Inaddition, the curvatures of light emission surfaces 333A to 333E are setso that the lights La to Le emitted from a first region 331A to a fifthregion 331E are parallel to the optical axes of light sources 321A to321E. However, in the case of such a configuration, since the amount oflight emitted toward the surrounding portion of the concave mirror 326is reduced, there is a problem that the luminance of the surroundingvirtual image portion of the virtual image object generated by thereflected light of the concave mirror 326 is reduced. In order tosuppress the luminance reduction of the surrounding virtual imageportion, in an example of the related art, for example, a diffusion lensfor diffusing the light La to Le emitted from the first region 331A tothe fifth region 331E has be required to be added.

On the other hand, the HUD 20B according to the second embodimentincludes the image generation unit 24B emitting the light for generatingthe predetermined image the concave mirror 26 for reflecting the lightso that the windshield 18 is irradiated with the light emitted by theimage generation unit 24B. The image generation unit 24A includes atleast the first light source 221A to the fifth light source 221E and thesingle lens 230 transmitting the light from the first light source 221Ato the fifth light source 221E, and the first light source 221A to thefifth light source 221E are disposed at the pitch matching the shape ofthe concave mirror 26 so that the light emitted from the single lens 230is diffused and is incident on the concave mirror 26. According to thisconfiguration, the uniformity of a luminance distribution of the virtualimage object I generated by the reflected light of the concave mirror 26can be improved by allowing the diffused light to be incident on theconcave mirror 26 from the single lens 230. As a result, the visibilityof the virtual image object I can be improved. In addition, since theoptical member for obtaining diffused light can be configured with thesingle lens 230, there is no need to add the separate member such as adiffusion plate, and the size and the cost of the HUD 20B can bereduced.

In addition, with this configuration of the HUD 20B, the single lens 230has the first region 231A to the fifth region 231E of the lens 230 whichare the plurality of convex surface portions disposed in parallel alonga parallel direction of the first light source 221A to the fifth lightsource 221E so as to emit light from each of the first light source 221Ato the fifth light source 221E. The first light source 221A to the fifthlight source 221E are disposed so that the pitch of the first lightsource 221A to the fifth light source 221E is shorter than the pitch ofthe respective vertices of the first region 231A to the fifth region231E of the lens 230. According to this configuration, when the pitchbetween the light sources is allowed to be equal to the pitch betweenthe vertices of the light emission surface (convex surface) of the lens,the light emitted from each of the regions 231A to 231E of the lens 230toward the concave mirror 26 can be diffused. Accordingly, theuniformity of the luminance distribution of the virtual image object Ican be improved.

In addition, with this configuration of the HUD 20B, the light emittedfrom each of the first region 231A to the fifth region 231E of the lens230 is configured to be perpendicularly incident on the concave mirror26. With this configuration, since light can be uniformly reflected onthe entire concave mirror 26, the uniformity of the luminancedistribution of the virtual image object I can be further improved.

In addition, with this configuration of the HUD 20B, the predeterminedimage (virtual image object I) is formed in a horizontally-longrectangular shape, and the shape of the region emitting the light toform the center of the predetermined image and the shape of the regionemitting the light to form the end of the predetermined image areallowed to be different from each other among the first region 231A tothe fifth region 231E of the lens 230 which are the plurality of convexsurface portions disposed in parallel. According to this configuration,even the light for forming the end of the predetermined image can beincident on the concave mirror 26 in the substantially perpendicularstate, and the uniformity of the luminance distribution of the virtualimage object I can be further improved.

While the embodiments of the present invention have been describedabove, it goes without saying that the technical scope of the presentinvention should not be limitedly interpreted by the description of theembodiments. It should be understood by those skilled in the art thatthis embodiment is merely an example, and that various modifications ofthe embodiment are possible within the scope of the invention describedin the claims. The technical scope of the present invention should bedetermined based on the scope of the invention described in the claimsand their equivalents.

The above-described embodiment has the configuration where thewindshield 18 is irradiated with the light emitted from the imagegeneration units 24 (24A and 24B) that is reflected by the concavemirror 26, but the configuration is not limited to this. For example,the combiner (not illustrated) provided in the windshield 18 may beirradiated with the light reflected by the concave mirror 26. Thecombiner is configured with the transmission member, for example, thetransparent plastic disc. The portion of the light emitted from theimage generation unit 24 of the HUD body unit 21, with which thecombiner is irradiated, is projected into the viewpoint E of theoccupant in the same manner as when the windshield 18 is irradiated withlight.

In addition, in the above-described embodiment, the case where the HUDis mounted on the vehicle has been described, but the present inventionis not limited thereto. For example, the HUD may be mounted on amotorcycle, a railroad, an aircraft, or the like. In addition, in theabove-described embodiment, it is described that the vehicle operatingmode includes the fully automatic operating mode, the advanced operatingsupport mode, and the operating support mode, and the operating mode ofthe vehicle should not be limited to four modes. The operating modes ofthe vehicle may include at least one of these four modes. For example,only one of the operating modes of the vehicle may be executable.

In addition, classification and a display form of operating modes of avehicle may be appropriately changed in accordance with the laws andregulations related to automatic operation in each country. Similarly,the definitions of the “fully automatic operating mode”, the “advancedoperating support mode”, and the “operating support mode” described inthe description of the present embodiment are only examples, and lawsand regulations related to the automatic operation in each country maybe changed as appropriate.

This application is based on Japanese Patent Application No. 2020-204214filed on Dec. 9, 2020, the contents of which are incorporated herein byreference.

1. A head-up display configured to display a predetermined image, thehead-up display comprising: an image generation unit emitting light forgenerating the predetermined image; and a mirror reflecting the light sothat a transmission member is irradiated with the light emitted by theimage generation unit, wherein the image generation unit includes: alight source; an optical member transmitting light from the lightsource; and a liquid crystal unit in which an original image for formingthe predetermined image is generated by the light emitted from theoptical member, wherein the original image is formed in a shapecorresponding to distortion of the predetermined image, and wherein theoptical member is formed in a shape matching the shape of the originalimage.
 2. The head-up display according to claim 1, wherein the shape ofthe optical member is a curved-line shape.
 3. The head-up displayaccording to claim 2, wherein the light source includes a plurality oflight sources; wherein the optical member includes a plurality of convexsurface portions transmitting light from each of the plurality of lightsources, and wherein the plurality of light sources are disposed in acurved line as viewed from the liquid crystal unit side, and theplurality of convex surface portions are disposed in a curved line asviewed from the liquid crystal unit side.
 4. The head-up displayaccording to claim 3, wherein the predetermined image is formed in ahorizontally-long rectangular shape, and a degree of distortion of endregions of the predetermined image is larger than a degree of distortionof a central region of the predetermined image, and wherein a shape ofthe convex surface portion disposed corresponding to the central regionand a shape of the convex surface portion disposed corresponding to theend region are allowed to be different from each other among theplurality of convex surface portions according to a difference betweenthe degree of distortion of the central region and the degree ofdistortion of the end regions.
 5. A head-up display configured todisplay a predetermined image, the head-up display comprising: an imagegeneration unit emitting light for generating the predetermined image;and a mirror reflecting the light so that a transmission member isirradiated with the light emitted by the image generation unit, whereinthe image generation unit includes at least: a plurality of lightsources; and a single optical member transmitting light from each of theplurality of light sources and emitting the light, and wherein theplurality of light sources are disposed at a pitch matching a shape ofthe mirror so that light emitted from the single optical member isdiffused and is incident on the mirror.
 6. The head-up display accordingto claim 5, wherein the single optical member has a plurality of convexsurface portions disposed in parallel along a parallel direction of theplurality of light sources so as to emit the light from each of theplurality of light sources, and wherein the plurality of light sourcesare disposed so that a pitch of the plurality of light sources isshorter than a pitch of each vertex of the plurality of convex surfaceportions.
 7. The head-up display according to claim 6, wherein the lightemitted from each of the plurality of convex surface portions isconfigured to be perpendicularly incident on the mirror,
 8. The head-updisplay according to claim 6, wherein the predetermined image is formedin a horizontally-long rectangular shape, and wherein a shape of theconvex surface portion emitting light for forming the central region ofthe predetermined image and a shape of the convex surface portionemitting light for forming the end region of the predetermined image areallowed to be different from each other among the plurality ofjuxtaposed convex surface portions.